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Registered
Join Date: Apr 2003
Location: Terre Haute, IN
Posts: 2,949
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Aftermarket cam QUALITY CONTROL?
I had a lengthy discussion about camshafts and aftermarket cam quality with a known engine builder who flows heads and builds some racecars in the midwest. He points out that he has found several problems/issues he has found with the aftermarket camshafts out there.
*Timing from left to right side is inconsistent. *Even if front lobes check for separation OK, often times back cylinder lobes usually don't. *Lobe lifts are not in spec on many of the lobes (lesser issue) *Base circles are all over the place *Has seen cam timings off 15 degrees R to L *False claims of coatings that are easily removed *Audible bank to bank exhaust notes that were later tied to camshafts not paired well *That many grinders are causing some of these problems by using the same blank and simply flipping the blank for the other side. This obviously gives less than ideal profiles on the lobes. It also doubles the adv/ret when you do this refering back to earlier mentioned problems. If this is how they are doing it, I don't want to buy into this. My question about this builder is even though he talked a good game and had everything good to say about Porsche OEM cam, is that he was down on just about everyone out there. He strongly suggested that straying from OEM was a crap shoot. His negativity is probably going to work against him getting my work but I want your opinions. My observation is that aftermarket cam grinders have to be kept in check in any make car. Most of the really fast guys are running aftermarket grinds like aftermarket GT2's. I guess I don't buy that everyone is clueless on grinding a variable rocker cam for a 911 after some 40 years of existence. What I'm looking for is WHAT ARE BUILDERS FINDING IN THEIR QC ON BUILD UPS? People who are making or grinding cams feel free to PM but be careful on responding directly to this thread just in case it gets ugly.
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Luke S. 72 RS spirit 2.7mfi, 73 3.2 Hotrod on steelies, 76 993 3.3efi TT, 86 trackrat, 91 C4s widebody,02 OLA winning 6GT2, 07 997TT, 72 914 v8,03 900 rwhp 996TT |
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03-09-2007, 06:05 AM
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Hi Luke:
I cannot speak for anyone else, but we've been using Webcam & Dema Elgin's products with no issues for a long long time. Race engines get degreed on each cylinder and I've not seen improper lobe profiles on any regrinds or new billet ones, yet. If something looks suspicious, it gets checked with the Cam Doctor.
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Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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03-09-2007, 02:10 PM
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Registered
Join Date: Dec 2003
Location: Arapahoe County, Colorado, USA
Posts: 9,032
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Luke,
I agree with Steve. He and I have been around this for a very long time. You hit the important issues. A good builder like Steve has found some vendors he can trust. The way to find that out is to be able to measure everything better than a vendor (even Porsche) can build it. Start by not trusting ANY part. This is the reason professional race engine builders are expensive, they check everything. As you know, that is very time consuming. About a year ago a builder friend found a new OE Porsche Racing GT3 oil pump that was cast/machined defective. Don’t trust anything. Check everything. Best, Grady
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03-09-2007, 06:10 PM
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